1. Field of the Invention
This invention relates to a simulated moving bed chromatographic separation system, particularly to a simulated moving bed chromatographic system capable of evaluating the separation performance of the unit packed beds of the system without removing the packed beds from the system.
2. Prior Art
In recent years, the simulated moving bed chromatographic system has been frequently and broadly used for separation or purification of various chemical products such as drugs, pharmaceuticals, agrochemicals, perfumes, sucrose, etc.
In general, the simulated moving bed chromatographic separation system for separating from a feedstock the constituents thereof, such as drugs, pharmaceuticals, agrochemicals, perfumes, sucrose, etc., is provided with a fluid circulating passage through which a liquid (hereunder referred to as "circulating liquids") flows and which has at least four columns containing separating fillers packed therein, connected in series and endlessly to each other by piping, a desorbing liquid introducing port for introducing the desorbing liquid into the fluid circulating passage, an extract draw-out port for drawing out a circulating liquid containing a larger amount of constituents in the feedstock to be strongly adsorbed on the fillers (hereunder referred to as "extract"), a feedstock introducing port for introducing the feedstock containing the constituents into the fluid circulating passage, and a raffinate draw-out port for drawing out a circulating liquid containing a larger amount of constituents to be weakly adsorbed on the fillers (hereunder referred to as "raffinate"). The desorbing liquid introducing port, extract draw-out port, feedstock introducing port and raffinate draw-out port are arranged in this order on the fluid circulating passage and designed so that their positions may be intermittently shifted without changing this order.
Operating the simulated moving bed chromatographic separation system for a long time causes the fillers in the columns to be deteriorated or the performance of the columns or piping to be reduced due to deposition of impurities on the columns or piping. Therefore, the purity of the strongly adsorptive constituents in the resulting extract or the weakly adsorptive constituents in the resulting raffinate may be lowered.
In such case, prior art simulated moving bed chromatographic separation systems have in general been examined by removing the columns from the fluid circulating passage, mounting the columns one by one on a high-speed chromatographic apparatus and then evaluating the separating performance of the columns.
Thus, the examination operation is complicated, and it takes a long time to know which column is deteriorated.
Furthermore, when the separating performance of the columns evaluated for by the high-speed chromatographic apparatus are again mounted on the fluid circulating passage, the packings or O-rings on the ends of the columns may be damaged, so liquid leakage may occur at the ends of the columns.